Method for shearing solids in a solids-liquid suspension

ABSTRACT

A method for dis-aggregating solid particles in a slurry by pumping the slurry at pressures in excess of 1,000 p. s. i. through a column containing particulate media clamped in a fixed position is disclosed.

United States Patent Iannicelli 1 June 6, 1972 METHOD FOR SHEARINGSOLIDS IN A SOLIDS-LIQUID SUSPENSION Inventor: Joseph Iannicelli, Macon,Ga.

Assignee: J. M. Huber Corporation, Locust, NJ.

Filed: Nov. 16, 1970 Appl. No.: 89,973

Related US. Application Data Division of Ser. No. 740,955, June 28,1968, Pat. No. 3,556,416.

U.S. CI ..241/1, 241/30 Int. Cl. ..B02c 19/00 Field ofSearch.....241/l,5,15,30

ZO K

Primary Examiner-Granville Y. Custer, Jr. Attorney-Harold H. Flanders 57] ABSTRACT A method for dis-aggregating solid particles in a slurry bypumping the slurry at pressures in excess of 1,000 p. s. i.

through a column containing particulate media clamped in a fixedposition is disclosed.

4 Claims, 10 Drawing Figures PATENTEUJUH s 1972 SHEET 1 OF 2 METHOD FORSHEARING SOLIDS IN A SOLIDS-LIQUID SUSPENSION CROSS-REFERENCE TO RELATEDAPPLICATION This is a division of application Ser. No. 740,955, filedJune 28, 1968 now US. Pat. No. 3,556,416 issued Jan. 19, 1971.

BACKGROUND OF THE INVENTION In general, the present invention relates tosolid-liquid suspensions and more specially to a method for shearingsolids in such suspensions.

In particular, the invention relates to the method for reducing the sizeof particles suspended in a slurry by forcing the slurry through acolumn packed with relatively coarse, hard, substantiallynon-deformable, non-flowable discrete aggregates including both abrasiveas well as non-abrasive material in a wide variety of geometric shapes.

The high pressure pumping of slurries to shear the slurries and effectchanges in the characteristics of the solids is, of course, well known.Such pumping has been used for processes such as homogenization,dispersion of solids in fluids, reduction in viscosity and reduction inparticle size. In such uses, a resiliently biased orifice valve is usedto retard the flow of slurry from the pump to build pressure in the pumpand force the slurry at extremely high velocities through an orifice ina relatively thin film. In each of these uses the very high velocity ofthe slurry is such that the valve is quite quickly eroded away and mustbe replaced after a very short useful life.

Pumping as described above is, however, extremely efficient and evenwith the high maintenance cost in valve replacement is one of the mostefficient shear apparatus now available.

Accordingly, it is an object of the present invention to provide a new,highly effective method which overcomes the deficiencies of the priorart as described above while retaining at least a like efficiency ofoperation.

It is a further object of the present invention to provide a methodwhich will reduce the cost of the shearing operation in a solid-liquidsuspension.

Another object of the present invention is to provide a method ofoperation for achieving shearing in solid-liquid suspensions havingincreased reliability.

Other objects and a fuller understanding of the present invention may behad by referring to the following description and claims taken inconjunction with the accompanying drawings.

SUMMARY OF THE INVENTION The present invention overcomes thedeficiencies of the prior art and achieves its objectives by providing apacked column of hard substantially non-deformable, relatively coarseparticle size aggregates which provide a plurality of tortuous passagesthrough which a suspension of solids in a liquid is pumped at an inletpressure in excess of 1,000 p. s. i. In passing through the tortuouspassages a very rapid acceleration to very high velocities takes place.At the same time the suspension is exposed to an extreme turbulentcondition combined with shear, cavitation and impact as it impinges onthe surrounding aggregates. The process produces a dispersion of reducedparticle size which in some materials such as kaolin clay may resultfrom dis-aggregation and delamination.

BRIEF DESCRIPTION OF THE DRAWINGS In order to facilitate theunderstanding of the present invention, reference will now be made tothe appended drawings. The drawings should not be construed as limitingthe invention, but are exemplary only. In the drawings:

FIG. 1 is a perspective view of a high pressure pump.

FIG. 2 is a vertical cross-section taken through the column.

FIG. 3 is verticalcross-section taken along the line 3-3 of FIG. 2looking in the direction of the arrows.

FIG. 4 is a plan view of a screen support.

FIG. 5 is a vertical cross-section taken along the line 5-5 of FIG. 4looking in the direction of the arrows.

FIG. 6 is a plan view of the face of the screen support opposite theface illustrated in FIG. 4.

FIG. 7 is a plan view of the lower clamp member shown partially insection for convenience of illustration.

FIG. 8 is an end view of the structure illustrated in FIG. 7.

FIG. 9 is a side elevation of the upper clamp member and FIG. 10 is anend view of the structure illustrated in FIG. 9.

Referring now to the drawings in detail wherein like referencecharacters indicate like parts throughout the several figures.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An apparatus suitable forcarrying out the present invention is shown generally in FIG. 1 in whichthe reference numeral 20 indicates generally a high pressure pump whichmay be used in accordance with the present invention.

The high pressure pump 20 may be of any type developing in excess ofabout 1,000 p. s. i. with the pump illustrated being a Sub MicronDisperser Model 2050-MC45-5TBS as manufactured by Manton-GaulinManufacturing Company, Inc., Everett, Massachusetts. The pump, shownhere for purposes of illustration, is of a conventional piston cylindertype and has a column block 21 secured to the outlet 22 thereof. Abypass valve 23 communicates with the outlet end of the pump 20 and iscontrolled through a hydraulic line 24 to vary the pressure at which thebypass valve 23 will release. The bypass valve 23 is of conventionalconstruction. The bypass or relief valve may be a hydraulically loadedhomogenization type valve or a spring loaded release valve or similardevice. Obviously, any suitable pump capable of achieving the desiredpressures may be employed in accordance with the teachings of thepresent invention as a matter of choice. In particular, a pistoncylinder type pump need not be employed. Other type pumps such as thoseof the gas pressure or of the centrifugal type may be employed so longas they produce adequate pressure for the desired application.

The column block 21 is of generally rectangular cross section and isprovided with a central bore 25 extending completely through the top end26 and the bottom end 27 of the column block 21. An inlet bore 28extends horizontally from the central bore 25 through the side wall ofthe column block 21 near the bottom end 27 thereof. A recessed seal 29is arranged at the outer end of the inlet bore 28 and seals the columnblock 21 to the pump 20.

A threaded outlet bore 30 extends horizontally from the central bore 25through the side wall of the column block 21 near the top end 26thereof. The outlet bore 30 extends through the opposite side of thecolumn block 21 from the inlet bore 28.

A lower clamp member 31 has a generally cylindrical body 32 having anannular O-ring groove 33 formed therein. A reduced diameter extension 34is integrally formed on the body 32 and extends coaxially therewith. Theclamp member 31 is fitted with an O-ring seal 35 seated in the O-ringgroove 33. The O-ring seal 35 engagesthe surface of the bore 25 belowthe inlet bore 28 to prevent escape of pressure through the lower end ofthe bore 25.

A plate 36 is positioned in engagement with the lower end of the clampmember 31 and is secured to the column block 21 by a pair of threadedstuds 37 and nuts 38 as can be seen in FIGS. 2 and 3.

While the above description of the column block has been provided forpurposes of illustration it will be obvious to those skilled in the artthat many variations of the column block and its cross-section may beemployed while retaining its essential functions and without departingin substance from the teachings of the present invention.

A generally cylindrical screen support S is mounted in the bore 25 inengagement with the upper end of the extension 34. The screen support Shas a plurality of bores 39 extending therethrough with their axesparallel to the axis of the support S. The bores 39 are arranged in acircle adjacent the cylindrical wall of the support S. One end face 40of the support S is provided with a plurality of radially extendinggrooves 41 which each intersect one of the bores 39 and also intersecteach other at the center of the support S.

A plurality of screens 42 of graduated mesh are mounted on the support Sin engagement with the end face 40.

A body of particulate media 43 fills the central portion of the bore 25supported on the screens 42. A second set of screens 42 and a support Sengage the upper end of the body 1 of particulate media 43. An upperclamp member 44 has a cylindrical body 45 and a reduced diameterextension 46 integrally formed thereon and extending axially therewith.

A plate 47 is positioned against the upper end of the column The methodof the invention is practiced generally by selecting a particulate mediasuitable for the purpose and packing the column block 21 with thismedia. The clamp member 31 is tightened until the media is clampedsufliciently tight to prevent virtually all motion between particles ofthe media during the practice of the invention.

A particulate solid dispersed in a fluid is then pumped at a pressure inexcess of about L000 p. s. i. through the particulate media in thecolumn block 21. The operation may be repeated for as many passesthrough the particulate media as is required to produce the desiredproperties in the end product.

The following examples teach several of the preferred embodiments of theinvention.

block 21 and engages the upper end of the clamp member 44 EXAMPLE] and arecessed seal 48. The plate 47 is secured to the column A 68 5 s lids luf f d l h block 21 by a pair of stud bolts 49 and nuts 50. The upper olet 1 2 ay 2 2 clamp member 44 bears against the upper screen support S toand l 6 497 0 i f f g mlcrotis position it within the bore 25.Adjustment of the lower plate throu 02mm acied z zgi 36 by means of thenuts 38 exerts varying clamping pressure g p p a umma ceram'c tharticulate media 43 and ma be ti htened as re uired beads 0H2 to 18 meshm Size 8; thsfondifions y g q The resulting clay product had a particlesize of 37.6 percent-2 i rons, 32.8 The above description of anapparatus suitable for carrying 10 g i percent s mlcmns and 13 7 percentt nv io utilizin su ort screens should not out the presen I l n g p Thefollowing table illustrate additional examples showing be understood tolimit the present invention to such an art S if a" 1i ation will sufficeto the materials used and the results obtained. rangemen R f m many.appc In Table I above the reference letters are explained as folorder theparticle size of the particulate media in a decreasing lows manner thecenter of the column from each, h A. Tumblex 12 XM: A highly abrasiveceramic frit obtained the larger particles at each end of the columnserving wholly from the Norton Company or in part to restrain thecentral particlesof the column. In B Tumblex A high alumina prismapproximately general any name clampmg or restfmnfng means "S be fourthinch per side and three thirty-seconds inch thick utilized in lieu ofthe screens to function in accord with the obtained from the Nortoncompany present invention. Further, as will become increasingly clear,LC Tumble, TL; Ceramic cylinders ya X obtained the present invention isin no way limited by the details of the f the Norton company P and p gmechanisms disclosed above y y of D. Plexiglass Rods: Cylinders as X 54;inch obtained from example, but any similar suitable means may beemployed to a R h & H like end. E. 20 25 Mesh Ottawa Sand: Obtained fromOttawa Silica In carrying out the method of the present invention the c,o pump 20 is operated in a normal manner to pump a fluid F. 7 -12 MeshAlundum Beads: Alumina spheres obtained dispersion of particulate solidthrough the column 21 of from Minnesota Mining and Manufacturing. packedparticulate media 43 at a predetermined pressure. The G. Talc: Equalparts of Nytal 200 and Nytal 300 tales obindividual particles of' thedispersed particulate solid are tained from Gouvenuer Talc Company.reduced in size by attrition, fracturing and delamination. Tables I andII illustrate the reduction in particle size of the TABLE I Percent -2nii- Percent Pressure psi. crnns at 2 miicrccl it bcgi ncrons at ExmnploMaterial treated solids l'm'ticulutn media 1st pass 2nd puss 3rd passuiug finish 0 ll 1 '1 1' .llll '1'; "u 'lumlllnx 12x11 (1) 3.3011 31.130.

M iii Iii I L. 'i'll 'lumlllut 'llr (ll). 1 31,1 37, 1V V fin du'lumhlvxll.(( 31.1 36,1 V 1 Product from Example l\" 7t) 7 (l p H n U 72 7! VI U Product from Example V 70 l0 I. 1 38.1 VII V Kaolin coarsefiller grade". 70 lhixiglns's ltmls (l)) 31.1 32, Vlll Product fromExmnplcvll 70 .....(lo 32. 34.3 lX. Product from Example Vlll. 70 .0110A, X Kaolin coarse llllcr grade 30 20 -25 mesh Ottawa. snml (E). 31.137, 1 XI Talc (G) 1O 7-121nusll uluudum heads (I") 1&1 11g; XII do 10 d015.2 1%,; XIII do 10 d0 16.4 1b.;

TABLE II Percent Percent; 2 n1i- 2 mi- Solids, Number crons at crons atExample Material treat-ed percent P.s.1 passes Particulate mediabeginning finish 2,700 1 Tumblox 12XM. 9.0 11.5, IX Talc s0.4s{ g 4 i2lg? 1,700 16.2 18. 2,650 1 Tumblox 12 XM. 8. 5 0. 2 r r o X Feldspur31.2 4 5:: {5 1,625 12. 5 13.11 1,650 11.4 11.0

1 9 XI Calcium carb01mte 36.3 l a; 1,450 10 12.5 12.0 2, 700 1 Tum blex12 XM. 11. 2 13. 4 I) 1 XIL Nepholinc syenitru. 37. l 1. 000 18.1

TABLE III f....fii9 material treated with wide variations in thepressures, solids 1 2 2 553 53 2 2 3 content, particulate media and ofthe material treated.

Table III illustrates the reductions in viscosity which result from thepractice of the invention. 5 In Table III the reference letters areexplained as follows:

H. Diamonite one-fourth inch: one-fourth inch hi-density radius endfused alumina cylinders obtained from U. S. Stoneware. I. Hi-Densityone-fourth inch Cyl: one-fourth inch fused alumina hi-density flat endcylinders obtained from U. S.

Stoneware.

J. Stainless Steel Balls one-fourth inch: one-fourth inch spheres ofstainless steel obtained from U. S. Stoneware, 5 m 5' O O I to Q 0) 6 oioi oi oi oi oi :60: Akron H H H H H H H K. Lucite Balls three-sixteenthsinch: three-sixteenths inch spheres of polymethylmethacrylate obtainedfrom Ace Plastic Co., Inc.

The examples demonstrate that the high pressure pumping of solidsdispersed in a fluid through a column packed with particulate media willreduce the particle size of the dispersed solid and also reduce theviscosity of the treated material. Ezgggggzg In carrying out theinvention any material exhibiting suita- H H ble properties of hardness,substantial non-deformability and available in durable, relativelycoarse particle sizes may be employed to provide the plurality oftortuous passages through which the solid-liquid suspension is passed.Typical materials of suitable hardness include ceramic frits, alumina,sands, stainless steels, Lucite, Plexiglass, silicon oxides, tungstencarbide, titanium nitride, zirconium carbide, beryllium carbide,titanium carbide, silicon carbide, aluminum boride, boron carbide andthe like.

The shape of the particles of the particulate media will generally bespherical, quasispherical, spheroidal, or 35 polyhedral and should not,in general, have many jagged edges since such edges lead to a knittingeffect which increases the pressure requirements. This latterconsideration is not intended to exclude, however, the use of suchmaterials under certain operating conditions for specific suspensionswhere 40 the knitting effect is not significant or the increasedpressure requirements are not significantly objectionable. Further,nothing above is meant to exclude any shape of particulate sec. perBrooksec. per 100 revofield cps. 100 rcv0- lutions '20 rpm. Herculeslutions 150 N0, 1 dyne units/ 150 r.p.m. g. wt." spindle r.p.m. g. wt.18/670 18/660 18/845 18/010 18/855 18/045 18/840 18/870 18/815 18/03518/850 18/915 18/850 18/750 18/705 18/940 18/910 field cps.

Hercules No. 1 dyne units/ spindle 20 r.p.m.

Number P s l of passes Particulate media 0 3, 1 Diam0nite%(H) 2, 2.....do 3, l Hi-density cyl (I).... 2, 2 d0 2, 1 Stainless steel balls2, 2 do 0 4, 1 Lucite balls ,45 (K)- vention as disclosed herein. Forexample, certain geometric combinations of tetrahedras, in addition tothose naturally occurring, have been found quite satisfactory as a shapefor the individual particles of the media in the operation of thepresent invention.

The length of the column through which the suspension is to be passed isproportionally related to the initial pressure and the amount ofpressure drop across a given length of the column, with a large portionof the work on the solids in suspension believed to be performed in theinitial portions of the column.

In addition to the single column shown, several obvious variations toone of ordinary skill in the art may be employed. For example, a singleelongated column with decreasing particle size throughout may be used.Alternatively a single high pressure pump may be employed to force thesuspension through a plurality of individual columns in a serialarrangement with each column packed with particles of decreasing size.Another alternative is the provision of a plurality of pumps each pumpbeing placed just prior to respective members of a plurality of columns.An additional alternative is the 6 provision of a plurality of columnsin a parallel arrangement for funneling the suspension through one ormore columns of finer particle size. Any combination of the abovearrangements may be employed or modified to meet the needs of theparticular materials and exigency of the occasion.

As many passes of the material through a given column as are desired orrequired may be made to achieve the desired particle size and/orviscosity; however, in general, an excessive reduction in particle sizeby continued repeated passes will result in an undesirable increase inviscosity.

While the invention has been described with reference to its WKpreferred embodiments, it will be understood by those skilled Percentsolids Material treated pumped Hydrasperse (No. 2 coating grade clay)kaolin clay control. IIydrasperse kaolin clay. H dm'sbis' ir'a'diiiiiiiitibijffIIIIIIIIIIIIIIIIIIIIII Hydrasperse kaolin clay. l8 dyne unitsis maximum torque recorded on viscometer; higher r.p.m. at 18 dyne unitsrepresents lower viscosity. "Lower time units per r. p.m. representslower viscosity.

Example XIIL XIV XV .d0 XVI. do XVII do XVIII. .t d0 XIX do materialwhich otherwise meets the needs of the present in-.

in the art that various changes may be made and equivalents substitutedfor elements and steps thereof without departing from the true spiritand scope of the invention. In addition, many modifications may be madeto adapt a particular situation or material to the teachings of theinvention without departing from its essential teachings.

WHAT IS CLAIMED IS:

1. The method of reducing the particle size of a solid dispersed in aslurry comprising pumping the dispersion at a pressure in excess of1,000 p.s.i. through a clamped body of a particulate media.

2. The method of claim 1 wherein the percent solids in the dispersion isin a range of from about 10 to about 80 percent.

3. The method of shearing and reducing the particle size of solidsdispersed in a slurry by dis-aggregation, attrition, fracturing anddelamination of the solids comprising:

a. providing a solids-liquid suspension wherein the percentage of solidsis in the range of from about 10 to about 80 percent and wherein atleast 8.5 percent of the solids have a particle size less than 2 micronsand a predominant portion of which have a particle size less than 10microns;

. restraining a particulate media comprising a plurality of hard,durable,. substantially non-deformable, non-flowable discrete particlesa substantial portion of which have dimensions on the order of theparticle size range of from about 25 mesh to about one-fourth inchwithin the central bore of a column; and

pumping said solids-liquid suspension at an inlet pressure in excess of1,000 pounds per square inch through the

2. The method of claim 1 wherein the percent solids in the dispersion isin a range of from about 10 to about 80 percent.
 3. The method ofshearing and reducing the particle size of solids dispersed in a slurryby dis-aggregation, attrition, fracturing and delamination of the solidscomprising: a. providing a solids-liquid suspension wherein thepercentage of solids is in the range of from about 10 to about 80percent and wherein at least 8.5 percent of the solids have a particlesize less than 2 microns and a predominant portion of which have aparticle size less than 10 microns; b. restraining a particulate mediacomprising a plurality of hard, durable, substantially non-deformable,non-flowable discrete particles a substantial portion of which havedimensions on the order of the particle size range of from about 25 meshto about one-fourth inch within the central bore of a column; and c.pumping said solids-liquid suspension at an inlet pressure in excess of1,000 pounds per square inch through the central bore of said column toforce said solids-liquid suspension through the body of said particulatemedia wherein said discrete particles provide a plurality of tortuouspassages producing high shear on said solids as said suspension ispumped through the column.
 4. The method of claim 3 further includingadjusting the restraining pressure on said particulate media so as toprevent substantially all movement by the particles of said media whensubjected to the flow of said suspension.